A variety of polycarbonate bottles, including the popular Nalgene shatter-free bottles contain the chemical bisphenol A. In sufficient quanitities the chemical is believed to disrupt hormones, but the FDA concludes in an early report that the levels in plastics are low enough not to be harmful.

FDA continues its insistence that the plastic is safe, says its studies on mice more accurate than recent human study

Last month, DailyTech reported that in a preliminary review, the U.S. Food and Drug Administration had declared the plastic Nalgene safe. While Nalgene and other products contain the hardening agent bisphenol A (BPA), a known disruptive agent of human physiology, the FDA concluded that sufficient quantities of the chemical did not leach into the liquids stored inside the bottles to cause harm. Critics blasted the ruling, pointing out that studies have indicated that small, but significant quantities did leach into the water.

Now the first major study on the effects of bisphenol A has been completed and it indicates a clear link between the compound and diabetes and heart disease. In the study, researchers from Britain and the University of Iowa examined a U.S. government health survey of 1,455 adults who had given urine samples. The adults were then split into different groups based on the levels of BPA found in their urine. All the adults were within the "safe" levels of BPA, according to the FDA's standards.

The study discovered that in the highest BPA group there were more than twice as many people with diabetes and heart disease. No correlation between BPA and cancer was shown.

While the study certainly seems to indicate a clear link between BPA and these diseases, it raises a chicken and egg sort of debate. If the findings hold true in additional tests, there are two possibilities. One possibility is that the disease came first and somehow raised the body’s absorption of BPA. The other possibility is that the BPA came first and somehow interact with the patients' bodies, putting them at higher risk of diabetes and heart disease.

Despite the fact that the largest study to date now suggests a link between "safe" BPA levels and disease, the FDA is refusing to change its stance. In a scientific review the FDA declared that BPA is "safe" within suggested guidelines. Laura Tarantino, head of the FDA's office of food additive safety, states, "Right now, our tentative conclusion is that it's safe, so we're not recommending any change in habits."

Tarantino says that if customers want to voluntarily avoid the chemical; that is their decision. She says that bottles bearing the recycling symbol 7 are BPA-containing, and that heating food in these containers helps to release the BPA.

Ms. Tarantino and the FDA also argued that the agency's own studies on mice were more thorough and extensive than the recent human study. The American Chemistry Council, an industry trade group, agreed and was quick to blast the study, saying it was flawed, substantially limited, and "proved nothing".

Several states are restricting BPA use, and there is legislation that may soon ban BPA use in baby bottles in Canada. On a national level in the U.S. and in the European Union, the government food and health agencies have suggested that the compound is safe. The FDA has acknowledged in the past that its own studies indicate "some concern" of the possible effects of BPA exposure on the brain in fetuses, infants and children. BPA is commonly used in baby bottles in the U.S. and EU.

“And I don't know why [Apple is] acting like it’s superior. I don't even get it. What are they trying to say?” -- Bill Gates on the Mac ads